Researchers Demonstrate Teleportation Using On-Demand Photons From Quantum Dots (phys.org)

An anonymous reader quotes a report from Phys.Org: A team of researchers from Austria, Italy and Sweden has successfully demonstrated teleportation using on-demand photons from quantum dots. In their paper published in the journal Science Advances, the group explains how they accomplished this feat and how it applies to future quantum communications networks. Scientists and many others are very interested in developing truly quantum communications networks -- it is believed that such networks will be safe from hacking or eavesdropping due to their very nature. But, as the researchers with this new effort point out, there are still some problems standing in the way. One of these is the difficulty in amplifying quantum signals. One way to get around this problem, they note, is to generate photons on-demand as part of a quantum repeater -- this helps to effectively handle the high clock rates. In this new effort, they have done just that, using semiconductor quantum dots.

Prior work surrounding the possibility of using semiconductor quantum dots has shown that it is a feasible way to demonstrate teleportation, but only under certain conditions, none of which allowed for on-demand applications. Because of that, they have not been considered a push-button technology. In this new effort, the researchers overcame this problem by creating quantum dots that were highly symmetrical using an etching method to create the hole pairs in which the quantum dots develop. The process they used was called a XX (biexciton)--X (exciton) cascade. They then employed a dual-pulsed excitation scheme to populate the desired XX state (after two pairs shed photons, they retained their entanglement). Doing so allowed for the production of on-demand single photons suitable for use in teleportation. The dual pulsed excitation scheme was critical to the process, the team notes, because it minimized re-excitation.

Comments

No, although it's quite a tease

[raymorris]

The rule you may know as "nothing can go faster than light" is actually "information can't be transmitted at more than light speed". You can find ways of measuring "speed" that come out to a value greater than C, but in no case do those allow one to transmit information from here to there at a velocity greater than C. At least not if "here" and "there" are more than an atom apart.

In quantum theory specifically, there's something called the no-communication theorem.

One example of a tease is that it's believed using quantum entanglement, two observers at a distance can see the same effect at exactly the same time - as if they both had access to the two ends of a very long string (or cat), and both ends of the string do the same thing at the same time. However, neither end can *effect* the behavior, so they can't send information.

There are a lot of ways to get excited *thinking* something implies faster than light communication if you understand a little bit of quantum physics.

Re: No, although it's quite a tease

[jd]

You can presuppose ER!=EPR, but until you've a paper on arXix, that's a supposition.

ER=EPR doesn't violate light speed, it simply says the particles are at the same point. Space isn't absolute, so two observers can see different distances. That's allowed.

The question is whether it happens.

finally some privacy in our communications !

[swell]

"it is believed that such networks will be safe from hacking or eavesdropping due to their very nature."

Well isn't that special! Truly private communication. But wait, isn't that against government policy? Don't our governments want access to all our communication, without the bother of encryption? Don't they want back doors to our devices?

But maybe, just maybe, there is an exception for our masters in government, in police work, for corporate boardrooms and financial wheeler-dealers such that they can have the privacy denied to common citizens.